Heat exchanger tube spacers



Sept. 3, 1957 w. A. KATHoLl HEAT EXCHANGER TUBE sPAcERs 2 Sheets-Sheet 1Filed Jan. 27. 1954 INVENTOR WILLIAM Sept 3, 1957 w-. A. KATHoLl HEATEXCHANGER TUBE sPAcERs 2 Sheets-Sheet 2 Filed Jan. 27, 1954 INVEN-roRWILLIAM A. KATHOLI BY l /AT PRNEY HEAT EXCHAGER TUBE SPACERS William A.Katholi, South Charleston, W. Va., assgnor to Union Carbide Corporation,afcorporation of New York Appiication .anuary 27, 1954, Serial No.406,405

Claims. (Cl. 257-236)` This invention relates 'to tube spacers for heatexchangers such as converters and has for an object to provide animproved device of this class which is capable of supporting and spacingheat exchanger tubes so that less flexure may occur in them due tovibrations from causes within them or without, which is capable ofproviding ample space for the longitudinal ow of tempering tiuid withina shell and outside the tubes, which is capable of having the tubesheets of substantially less thickness especially when in use the tubesare under a compressive stress tending to aggravate any flexuraltendency in the tubes, and which is capable of eliminating thedisadvantages which prior eforts at supporting and spacing such heatexchanger tubes have possessed.

Heretofore the tube supports that have been used and suggested have notbeen satisfactory. ASuch a support must provide as its name impliesadequate support for not only one tube but all of them, tend to opposevibration or iiexure in them, yet permit adequate liow of shell fluidalong the tubes for eicient heat transfer between the liuids within theshell and tubes. One prior suggestion was a spoked wheel type washeraround a tube to space it from adjacent tubes, but such was found to beunsatisfactory when the heat exchanger tubes were horizontal. A moresatisfactory type of support for the tubes was known as the cloverleafdesign in which spaced lingers to contact each tube were cut in a plate.This provided more space around a tube by having the supporting plateperforated in a manner to provide several linger projections which toucheach tube surface, but such construction was of prohibitive cost inmanufacture. In brief the simple and inexpensive suggestions were eitherineiiicient by obstructing the desired liow of shell fluid or were notmechanically strong enough to supportrthe cumulative exure in all thetubes. These disadvantages are now believed to have been Veliminated forthe irst time in a simple construction that is both rugged and eiiicientfor its intended purpose.

Specifically, according to this invention supporting plates are arrangedwithin the shell at a distance apart of not more than sixty times a tubediameter. Around each tube is a perforation larger than the tube by aconvenient amount such as about of the tube radius. Instead of havingintegral fingers spacing the tube from the edge of the perforation aswas done in the cloverleaf design, separate flat faced or round pins areplaced transversely of a sheet before the tubes are inserted and held inplace against angular and longitudinal displacement. Such pins provideadequate bearing surface against the outer surface of a tube withoutdanger of any edge cutting into a tube. As tight a t as is desired canbe obtained by selection of appropriate thickness for the pins radiallyof a tube. In a preferred form the pin is of U shape with the legportions located in adjacent perforations. Such has the advantage ofkeeping the pin or U clip held against displacement angularly withoutthe necessity for welding it to the supporting plate. To retain thissame clip against longitudinal displacement the un- Connected endportions are bent toward one another.

aanslag Fatented Sept. 3, l57

2 The preferred embodiment contemplates the use of a support platecovering most of the cross section of the shell. The relatively .largeopen spaces around the plate periphery and within the perforationsaround each tube obstructedonly by the spacing pins, allow ample space`for the longitudinal iiow of tempering liuid. These full circular platesmay be spaced at sixty times the tube diameter. Thus in a heatVexchanger having a length of one hundred twenty times a tube diameter,one plate between tube sheets would be suflicient. A modification ofthis arrangement may be made by using semicircular support platescovering alternate halves of the tube bundle. Thus, in an exchangerhaving a length of one hundred twenty times the tube diameter, onesupport plate covering half of the shell cross section would be placedinthe center, and midway between this center half-plate and each end arecomplementary half-plates covering the opposite half of theshell'l'cross sectional area. These half'- plates would not be serving abaffle function of channeling the tempering uid transverse to the tubessince the main ow would still be longitudinal to the tubes as in thecase of the 'full diameter support plate. This modification would,however, allow support plates of nonweldable materialto be made fromsheets of half the size required for a full diameter plate.

Referring to the drawings Fig. 1 is an elevation partly in section of` aheat exchanger embodying this invention. Fig. 2 is an enlarged View atthe section line 2-2 of Fig. l. Fig. 3`isa section on the line 3-3 ofFig'. 2. Fig. 4 shows a detail of one of the spacing clips before beinginserted between atube and the spacing plate. Fig. 5 `is aviewcorresponding to Fig. 2 but of an embodiment of this invention inwhich both the double'pins of Fig. 4 `and the single'pins of Fig. 7 areused. Fig. 6 is a View corresponding toFig. 2 and Fig. 5 but showingstill another embodiment. Vof vthis invention in which all the spacingVpins are of the single type shown in Fig. 7. Fig. 7 is a section on theline 7 7 of Fig. 6. Fig. 8 shows a schematic arrangement of thesemi-circular supporting plates withoutthe tubes being shown.

As shown in Fig. 1 this heat exchanger comprises a shell 10, with tubes11 expanded into tube sheets 12 and 13 at their ends. Heads 14 and 15are for the ingress and egress of fluid passing through the tubes .11.Some convenient type passageways 16 and 17 connect with each of theheads 14 and 15. One or more tube supporting Vand spacing means 1S areprovided for at least every length of the tubes 11 equal to 60 tubediameters.

In this invention the tubeV supporting and spacing means 18 comprises aplate 19 radially supported from the shell 10 by a space 20 to permitlongitudinal flow of shell fluid. Preferably each plate 19 is secured tothe shell by an L-shaped bracket 21 welded to the shell for having theplate 19 attached thereto by a bolt 22 as shown in Fig. 2. Each plate 19is provided with a plurality of perforations 23 larger than the outsidediameter of each tube to allow shell uid to pass longitudinally as wellas transverselyof the tubes. from the supporting plate 19 by a number ofU-shaped clips 24, or-pins.' As shown in Fig. 2 each clip spans aL plateportion between a pair of plate perforations 23 at a location where thespacing between these perforations is a minimum. In this way eachspacing clip, 24 is retained against angular displacement. v

As shown in Fig. 3 the tubes 11 are expanded into a tube sheet 13 insome accustomed manner. The open or unconnectedends of each spacing clip24 are bent until substantially touching one another as Vshown at 25.This bending preferably takes place before the tubes are inserted. Toprevent the sides of the spacing clip bowing radially inward toward acenter of a perforation 23 during the bending of the end portions 25, amandrel of Each tube 11 is spaced 3 appropriate size may be insertedbetween the pins to hold them longitudinally contiguous to the sides ofthe perforations 23. As many as six spacing clips are used around eachtube. adjacent the periphery of the supporting plate 19.smallperforations 30 are made for one side of a clip 24.

In the embodiment illustrated in IFig. 5 three instead of six spacingpins are used. Some of the tubes 11 have all pins of the U or doubletype 24 shown in Fig. 4. Other tubes have all pins of the single type 26shown in Fig. 7. Either or both types may be used wherever convenient.However, where the single pins 26 are used then to prevent theirbecoming angularly displaced from their intended position it will befound desirable to weld yat least one end of a pin 26 to the plate 19 asshown at 27 in Fig. 7.

The embodiment illustrated in Fig. 6 is like that in the preceding Fig.5 except that all the pins are of the single type 26 and each is weldedat one end. Any number of either single or double pins may be used.Either three or four such pins have been found convenient. Preferably nomore than six spacing pins per perforation 23 are used because a largernumber tends to obstruct the ilow of shell tluid longitudinally alongeach tube.

In Fig. 8 is shown an arrangement for the tube supporting plates in theshell without the tubes, tube sheets, and heads being shown. In thisembodiment it is assumed the `tubes have a length between tube sheets of120 times the tube diameter. A semi-circular supporting plate 31 isplaced at a mid-position between the tube sheets and is of a size tosupport the tubes in a left side cross section of the shell.Semi-circular tube supporting plates 32 and 33 are each located midwaybetween the center plate 31 and a tube sheet. As illustrated theseplates 32 and 33 support the tubes in the rightor complementary half ofthe shell cross section. In this way each tube is supported so that notover sixty diameters of its length is unsupported. The supportingbrackets 21 are'shown diagrammatically in Fig. 8. The arrows in Fig. 8indicate how a major portion of the shell uid entering the shell throughan opening 34 adjacentxone head may pass out an'opening 35 adjacent theother head. These openings for shell .uid ingress and egress may belocated at either the top, bottom or sides or one disposed 180 from theother, as is well known in the heat exchanger art.

Heat exchangers embodying this invention have been built in two sizes.ln one size the tubes are ft. long between tube sheets and the shell l()ft; in diameter inside the shell. In the other size the same length isused but the inside diameter of the shell is ll ft. 6in. As statedpreviously the pins or clips 24 and 26 are preferably secured in placebefore the tubes are passed through the supporting plates. One tubesheet is secured to the shell, the support plates with accompanying pinsor clips are installed, the other tube sheet is secured to the otherend, and the tubes are threaded fromone end to the other and their endsare expanded within both tube sheets as is well known in this art.

Among the advantages of this invention may be mentioned that anefficient heat exchanger of the converter type is provided having thetubes adequately supported to suppress flexureof a degree tending toloosen the tubes in the tube sheets and enabling tube sheetsto bereduced in thickness roughly 40% by allowing the tubes to act ascolumns. Also adequate space is provided for the longitudinal movementof shell fluid along the tubes, next to the shell, and, when,semi-circular plates are used,` also somewhat Vtransversely of the tubesas shown by the curvedv arrows in Fig. 8, all of which makes forefficient heat transfer. By the termfconverterY is meant aheatrexchanger in which a chemical reaction takes place within the tubesso that the tubes are at a higher Vtemperature than the shell, causingthe tubes to be under a compressive stress. Heretofore tubularconverters have usually had Where no perforations 23 are located Y 4 thetubes bent to take up their change in length due to their being at ahigher temperature than the shell, but under this invention straightconverter tubes have been provided. When a heat exchanger tube is undercompressive stress and there is a tendency to vibrate due to a suddenchange of fluid pressure within the tube, or to other causes, suchvibration is likely to cause a permanent set or bend in the tube or elsethe vibration may loosen the tit of the tube within a tube sheet.Smaller clearances between the supporting pins and tubes are possiblewith this invention inasmuch as tubes not only have a snug running twithin each supporting plate but well over 50% of the cross sectionalarea of the shell is available for the flow of shell iluid with thisinvention whereby dead i spots may be eliminated and sutlicient heattransfer obtained with a minimum pressure drop with each of the tube and`shell iuids. In one use contemplated for this converter the tubescontain a catalytic material which reacts with `the tube fluid causingan exothermic reaction and resulting in the tubes being approximately 25F. hotter than is-the shell iluid, the tubes being under around 50 lb.per sq.- in. of internal pressure. As soon as the tubes become heated inuse and expand a tight enough t within the supporting plates takes placeso that some of the compressive stress in the tubes may be transmittedto the shell to sectionalize the stresses and reduce the total stressinboththe shell and tubes. Without the large space around the supportingplates and without the large space around each tube, this invention mayalso be applied to a heat exchanger having segmental battles, in whichevent the pins 24 or26 may be set in recesses in each tube perforation.lIts chief.use however is believed to be with constructions which do notuse segmental batlles but allow longitudinal flow of shell fluid alongthe tubes.

What is claimed is:

- l. In a heat exchanger having a shell, tube sheets adjacent the endsof rsaid shell, a plurality of tubes vextending between said sheets andhaving their end portions secured to the sheet .at each end of saidshell for transmission of stress longitudinally thereof, and a headadjacent each tube sheet through which tube iuid may pass, said shellbeing provided with a perforation adjacent each tube sheet and Vthroughwhich shell fluid may pass around and along said tubes, the combinationtherewith of the improvement enabling less thick tube sheets to be used,especially when said tubes are under a longitudinal compressive stress,said improvement including a supporting plate for at least substantiallysuppressing the combined exureV of at least some of said tubes,intermediate the tube sheets, connected to but spaced from said shell,said supporting plate having a perforation around each tube passingthrough it with some of the edge portions of `such perforation spacedfrom the tube, spacing and supporting pins between each tube and saidplate yand extending transversely of said'plate, and means for retainingeach pin against longitudinal and V'angular displacement with respect tothe tube with which it contacts.

2. A heat exchanger according to claim l in which said pins have theirend portions bentto preclude their removall longitudinally of said tubesin either direction.

3. A heat exchanger according to claim 2 in which said pins are ofgeneral U shape with their unconnected ends bent toward one another.

4. A heat exchanger according to claim 3 in which a number of saidU-shaped pins have their side portions passing through adjacentperforations in said supporting plate.

5. A heat exchanger according to claim l in which at least two tubesupporting plates are located intermediate the tube sheets and each suchsupporting plate is substantially semi-circular in shape.

6. A heat exchanger according to claim l, in which a major portion ofeach plate perforation is openfor the lot' of shell iiuid therethroughlongitudinally of its tube, and in which the number of pins between eachtube and its supporting plate is from 3 to 6, and each plate perforationis spaced from its tube by about the thickness of said pins.

7. A heat exchanger according to claim 1 in which at least a portion ofcertain of said pins extends through respective smaller perforationsoset from a plate perforation.

8. In a heat exchanger of the type having a plurality of elongatedtubes, a sheet at each end of said tubes to which they are anchored fortransmission of stress longitudinally of said tubes, means whereby lluidmay be supplied to and withdrawn from said tubes, a shell around saidtubes, means whereby a fluid may be supplied to and withdrawn from thespace within said shell and around the outside of said tubes, and atleast one plate between the tube sheets through which at least some ofsaid tubes are passed for supporting and spacing said tubes passingthrough it, the combination therewith of the improvement for supportingand spacing such tubes in a simplified manner while offering less of anobstacle to the tlow of a tempering uid longitudinally of said tubes andoutside of them, said improvement including said tube supporting andspacing plate being provided with a plurality of perforations throughwhich tubes are passed with the walls of each such perforation, spacedfrom, and substantially coaxial wtih the tube passing therethrough, andbifurcated spacing and supporting clips respectively passing throughltwo adjacent perforations with side portions of said clip in `differentperforations and each side portion of a clip extending longitudinally ofthe tubes between a tube and an edge of a plate perforation, each cliphaving its side portions connected at one end by a bridging portionextending across a narrow portion of said spacing and supporting platebetween adjacent perforations, and the opposite ends of said clip fromsaid bridging portion being bent toward one another to retain said clipagainst being withdrawn, whereby ample space is provided for thelongitudinal uid flow around each tube.

9. A heat exchanger according to claim 8 in which at least six clips arespaced substantially equidistantly from one another, and the oppositeside portions of each clip are attened for cooperation with a tube and awall of said perforations.

10. In a heat exchanger of the type having a plurality of tubesextending between tube sheets and along which a tempering fluid ispassed, and a supporting and spacing plate through which at least someof said tubes pass, the combination therewith of the improvementenhancing the support of such tubes from said spacing plate whileproviding little obstruction to movement of tempering tluid along thetubes on the outside thereof, said improvement including said spacingplate being provided with a substantially concentric perforation aroundeach tube, and a plurality of U-shaped clips each having one sideinserted longitudinally between a tube and an edge of its spacing sheetperforation and its opposite side inserted between an adjacent tubeandan adjacent edge of its spacing sheet perforation.

11. In a heat exchanger having a plurality of tubes extending betweentube sheets, and a supporting and spacing plate having perforationsthrough which at least some of said tubes pass intermediate their ends,the combination therewith of the improvement for reducing the cost ofsuch construction while at the same time allowing ample space for thelongitudinal flow of tempering fluid around and along such tubes andthrough said plate, said improvement including at least threelongitudinal spacing members around each tube between it and an edge ofsaid plate perforation, each such spacing member having substantiallyattened opposite faces, a head at one end and an opposite end portionthereof being deformable to retain them in position longitudinally.

12. The combination with a.spacing and supporting plate having a numberof perforations therein arranged in rows, of a plurality of heatexchange pipes, at least some of such pipes coaxially passing throughsaid perforations and spaced from the edges thereof, and removablespacers between each pipe and an edge of its perforation, each suchspacer being held against being angularly displaced by being held in twoadjacent plate perforations and being spaced angularly a substantiallyuniform amount from each adjacent spacer.

13. A combination according to claim 12 in which each spacer is ofgeneral U shape with its side portions spacing pipes in adjacent holesand the connecting portion between the sides of the spacer spanning theportion of said plate of minimum width between adjacent perforationswhereby said spacer side portions are retained in position againstangular displacement by the connected side portion in an adjacentperforation.

14. A heat exchanger comprising in combination a shell, tubes, tubesheets to which the tubes are`connected at each end, a head outside ofeach tube sheet through which tube fluid may pass, a passageway adjacenteach tube sheet by means of which shell fluid may pass, at least onesupporting plate for said tubes between the tube sheets, said platebeing connected to but spaced from said shell, said supporting platehaving a perforation around each tube that passes through it with theedges of such perforations spaced from the tube, spacing and supportingpins extending transversely through said plate and secured thereto forpositioning each tube within its plate perforation, and means forretaining each pin against longitudinal and angular displacement withrespect to its tube, said means comprising each end of a pin being bentaway from said tube to retain it against longitudinal displacement andat least one bent end portion of said pin cooperating with said plate toretain said pin against angular displacement.

15. In a heat exchanger of the converter type comprising longitudinaltubes 'adapted to beplaced under compressive stress longitudinally, 'ashell around the tubes adapted to be placed under tension longitudinallythereof, tube sheets in which the tube end portions are anchored, a headon said shell beyond each tube sheet, the interior of each tube beingconnected to a space at each end of the shell between the head and tubesheet, a supply passageway for the fluid leading into one such space, adischarge passageway leading from the other such space" between a headand tube sheet, a passageway leading into the shell around said tubesadjacent one tube sheet, another passageway leading from said shell fromaround said tubes adjacent the other tube sheet, vand at least one tubesupporting plate intermediate the tube sheets, the combination therewithof the improvement providing a substantially rigid support for aplurality of said tubes intermediate their ends whereby flexure of saidtubes is reduced, less thick tube sheets may be provided, andlongitudinal stresses in the shell and in at least some of the tubessectionalized, said improvement including a plurality of spacing andsupporting members between each tube and the edge of its supportingplate, each such spacing and supporting member extending longitudinallyof its tube and transversely of its supporting plate, having its endsbent away from its tube, and held against angular displacement withrespect to its tube and another spacing member for its tube, all of suchspacing and supporting members contacting one tube occupying but a minorportion of the area of the plate perforation around the tube.

References Cited in the le of this patent UNITED STATES PATENTS 827,479Towne July 31, 1906 1,524,341 Davis Ian. 27, 1925 1,900,857 Berry et alMar. 7, 1933 2,219,327 Miller Oct. 29, 1940 FOREIGN PATENTS .466,199Germany Oct. 4, 1928

